The years leading up to the declaration of war between the Axis and Allied powers in 1939 were tumultuous times for people across the globe. The Great Depression had started a decade before, leaving much of the world unemployed and desperate. Nationalism was sweeping through Germany, and it chafed against the punitive measures of the Versailles Treaty that had ended World War I. China and the Empire of Japan had been at war since Japanese troops invaded Manchuria in 1931. Germany, Italy, and Japan were testing the newly founded League of Nations with multiple invasions and occupations of nearby countries, and felt emboldened when they encountered no meaningful consequences. The Spanish Civil War broke out in 1936, becoming a rehearsal of sorts for the upcoming World War — Germany and Italy supported the nationalist rebels led by General Francisco Franco, and some 40,000 foreign nationals traveled to Spain to fight in what they saw as the larger war against fascism.